Various consumer electronic products and other devices include a packaged light emitter module designed for precision light projection applications. The spatial dimensions of such modules generally need to be controlled to high precision, such that the optical elements and the light emitting element are precisely positioned, for example, at an optimal distance. Thus, the modules should have very small spatial (dimensional) and optical (e.g., focal length) tolerances for optimal performance. However, the use, for example, of adhesive in the packaged light emitter module, as well as other factors such as the inherent manufacturing tolerances of the pertinent support structure, often expand the tolerances of the module to an unacceptable level. The foregoing issues may be applicable to light detector modules as well.
For some applications, the light emitter module needs to operate at optimal optical performance over a relatively large temperature range (e.g., −20° C. 70° C.), which can raise various problems. First, the spatial dimensions of the optical elements and the support structure may vary with temperature. Second, the refractive index of the optical elements may vary with temperature. This latter variation may induce a variation in focal length, causing poor performance of the light emitter module. Further, the modules often require good heat conduction.